[PATCH] ARM: mvebu: DT: fix OpenBlocks AX3-4 RAM size

Jason Cooper [off-list ref] writes:

The OpenBlocks AX3-4 has a non-DT bootloader.  It also comes with 1GB of
soldered on RAM, and a DIMM slot for expansion.

Unfortunately, atags_to_fdt() doesn't work in big-endian mode, so we see
the following failure when attempting to boot a big-endian kernel:

The same will happen on kernels without the ATAG_DTB_COMPAT option
enabled too, right?

  686 slab pages
  17 pages shared
  0 pages swap cached
  [ pid ]   uid  tgid total_vm      rss nr_ptes swapents oom_score_adj name
  Kernel panic - not syncing: Out of memory and no killable processes...

  CPU: 1 PID: 351 Comm: kworker/u4:0 Not tainted 3.15.0-rc8-next-20140603 #1
  [<c0215a54>] (unwind_backtrace) from [<c021160c>] (show_stack+0x10/0x14)
  [<c021160c>] (show_stack) from [<c0802500>] (dump_stack+0x78/0x94)
  [<c0802500>] (dump_stack) from [<c0800068>] (panic+0x90/0x21c)
  [<c0800068>] (panic) from [<c02b5704>] (out_of_memory+0x320/0x340)
  [<c02b5704>] (out_of_memory) from [<c02b93a0>] (__alloc_pages_nodemask+0x874/0x930)
  [<c02b93a0>] (__alloc_pages_nodemask) from [<c02d446c>] (handle_mm_fault+0x744/0x96c)
  [<c02d446c>] (handle_mm_fault) from [<c02cf250>] (__get_user_pages+0xd0/0x4c0)
  [<c02cf250>] (__get_user_pages) from [<c02f3598>] (get_arg_page+0x54/0xbc)
  [<c02f3598>] (get_arg_page) from [<c02f3878>] (copy_strings+0x278/0x29c)
  [<c02f3878>] (copy_strings) from [<c02f38bc>] (copy_strings_kernel+0x20/0x28)
  [<c02f38bc>] (copy_strings_kernel) from [<c02f4f1c>] (do_execve+0x3a8/0x4c8)
  [<c02f4f1c>] (do_execve) from [<c025ac10>] (____call_usermodehelper+0x15c/0x194)
  [<c025ac10>] (____call_usermodehelper) from [<c020e9b8>] (ret_from_fork+0x14/0x3c)
  CPU0: stopping
  CPU: 0 PID: 0 Comm: swapper/0 Not tainted 3.15.0-rc8-next-20140603 #1
  [<c0215a54>] (unwind_backtrace) from [<c021160c>] (show_stack+0x10/0x14)
  [<c021160c>] (show_stack) from [<c0802500>] (dump_stack+0x78/0x94)
  [<c0802500>] (dump_stack) from [<c021429c>] (handle_IPI+0x138/0x174)
  [<c021429c>] (handle_IPI) from [<c02087f0>] (armada_370_xp_handle_irq+0xb0/0xcc)
  [<c02087f0>] (armada_370_xp_handle_irq) from [<c0212100>] (__irq_svc+0x40/0x50)
  Exception stack(0xc0b6bf68 to 0xc0b6bfb0)
  bf60:                   e9fad598 00000000 00f509a3 00000000 c0b6a000 c0b724c4
  bf80: c0b72458 c0b6a000 00000000 00000000 c0b66da0 c0b6a000 00000000 c0b6bfb0
  bfa0: c027bb94 c027bb24 60000313 ffffffff
  [<c0212100>] (__irq_svc) from [<c027bb24>] (cpu_startup_entry+0x54/0x214)
  [<c027bb24>] (cpu_startup_entry) from [<c0ac5b30>] (start_kernel+0x318/0x37c)
  [<c0ac5b30>] (start_kernel) from [<00208078>] (0x208078)
  ---[ end Kernel panic - not syncing: Out of memory and no killable processes...

Fix this by setting a sane default (1 GB) in the dts file.

Signed-off-by: Jason Cooper <redacted>

Tested-by: Kevin Hilman <redacted>

---
Kevin,

Please test when you have a moment.  If it works for you, feel free to apply it
directly wherever you feel it's appropriate.

Yes, this works for me as I've been using the same hack to boot several BE
kernels on the openblocks recently.

Could you do the minor changelog update above (ATAG_COMPAT), add the
Tested-by and send to arm at kernel.org so it gets tracked for arm-soc
merge.

Also, what do you think about backporting this for -stable?  At least
for v3.14+ since that's when BE started working.

Kevin